Dental hand instruments and covers for their head parts

Abstract

A medical, particularly dental, hand instrument (1) has a cover (30) on a head part (20). The cover has a lever mechanism (304) for releasing a holding mechanism arranged inside the head part (20). In this case, the lever mechanism (304) includes a first lever (320) and a second lever (330). An actuation (B) of the first lever (320) causes the second lever (330) to interact with and release the holding mechanism. This allows a treatment tool (7) to be attached to or detached from the head part (20) of the hand instrument (1).

Description

[Technical field]

[0001] The present invention relates to a hand instrument for medical use, particularly for dentistry. The hand instrument includes an instrument head and a treatment tool held in the instrument head. The treatment tool is attached to and detached from the instrument head via a holding mechanism. [Background technology]

[0002] A hand instrument of this kind is usually substantially composed of a grip sleeve and an instrument head (sometimes called a head part). The head part is arranged at the front end of the grip sleeve in order to operate the hand instrument easily and accurately. FIG. 6 shows a typical head part 20 arranged at the end of the grip sleeve 10 of a medical hand instrument 1. The head part 20 has a tool receiving opening 240. This allows different medical or dental treatment tools 7 to be inserted into the head part 20 depending on the application and to be connected to the hand instrument 1. To achieve this, a holding means 230 is provided inside the head part 20 for rotatably holding each treatment tool 7 (e.g. a dental drill). A release element 210 is connected to the holding means 230, which releases the holding of the treatment tool 7 in the holding means 230 when it is operated appropriately. During operation, the treatment tool 7 and the parts connected thereto (eg the release element 210 and the holding means 230) rotate at up to 450,000 revolutions per minute.

[0003] Up to now, a collet 230 is usually used to hold the treatment tool 7. When a push button switch 1000 is pressed and a wedge-shaped release element 210 acts on the collet 230, the latter releases the holding of the treatment tool 7. To achieve this, the push button 1000 usually comprises a push element 1001 and a compression spring 1040 which pushes the push button 1000 back in the opposite direction to its actuation. When the push button 1000 is actuated, the compression spring 1040 is compressed and the push element 1001 comes into contact with the release element 210 and presses it further into the holding means 230. When the push button 1000 is actuated sufficiently and the release element 210 is moved correspondingly sufficiently, the holding of the treatment tool 7 in the holding means 230 is released. The treatment tool 7 can then be removed from the tool channel 240 of the head part 20. Such a push button mechanism is usually implemented in a cover which can be attached to the head part 20 of the hand instrument 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] European Patent Application Publication No. 1 627 611 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the conventional arrangement with the push button 1000 and compression spring 1040 requires a relatively strong force to release the retention mechanism, because the interaction between the retention means 230 and the release element 210 requires a certain force (usually about 50 Newtons), in addition to the force required to exceed the spring force of the compression spring 1040. This makes the conventional mechanism difficult to operate and cumbersome.

[0006] Moreover, in this existing mechanism, even a slight actuation of the push button 1000 can cause the push element 1001 to come into contact with the release element 210, since it is only necessary to overcome the spring force of the compression spring 1040. However, contact of the push button 1000 with the release element 210 during operation poses a serious danger, since the contact of the push element 1001 with the release element 210, which has a high rotational speed, generates considerable friction, which leads to the push button 1000 heating up very quickly, which creates a serious risk of injury. Such a slight depression can be caused by the push button 1000 accidentally coming into contact with the teeth or cheek in the patient's oral cavity, which results in a risk of burns to the patient. Also, it is conceivable that the therapist may accidentally press the push button 1000 a little during treatment, which may also pose a risk of burns to the therapist.

[0007] Thus, conventional instrument heads having a push button mechanism for releasing the retention of a treatment tool are difficult to operate and pose a risk to both the practitioner and the patient.

[0008] Patent Document 1 also describes a medical handpiece head. In this handpiece head, a stroke motion along an axis is transmitted to a tool disposed in the handpiece head. In this case, the tool can be fixed at any position around the axis. The tool can be rotated around the axis as necessary, and can be prevented from rotating by a fixing mechanism.

[0009] The fixing mechanism is provided for establishing a clamping connection. To achieve this, the handpiece head is provided with a sleeve for receiving a tool, on which sleeve a first clamping part is arranged, and the grip part of the handpiece is provided with a second clamping part as part of the attachment part, which is pushed towards the handpiece head and interacts with the first clamping part to provide the desired clamping connection. The clamping mechanism described here is primarily intended for fixing the tool-holding sleeve with respect to the axis of rotation and not for releasable holding of the tool.

[0010] It is an object of the present invention to provide a medical hand instrument with an improved mechanism for operating a release element and a holding means for releasing the holding of a treatment tool inserted in the hand instrument, and a cover for a medical hand instrument having such an improved mechanism. [Means for solving the problem]

[0011] This object is achieved by what is stated in the independent claims. Particular embodiments of the invention are specified in the dependent claims.

[0012] According to the invention, a medical, in particular dental, hand instrument comprises a gripping sleeve and a head part arranged at the front end of the gripping sleeve and provided with a tool receptacle. A holding means for rotatably holding a treatment tool (e.g. a dental drill) is arranged inside the head part. The holding means is arranged along a rotation axis of the treatment tool. A release element is arranged inside the head part along said rotation axis. The release element is configured to interact with the holding means. The release element releases the holding of the treatment tool by interacting with the holding means. According to the invention, the head part further comprises a cover. The cover has a lever mechanism with a first lever and a second lever cooperating to release the holding of the treatment tool.

[0013] This allows the mechanism for releasing the grip of the treatment tool to be realised by the lever mechanism, in particular the arrangement of two co-operating levers which significantly reduces the force required to release the grip.

[0014] In addition to the hand instrument of the invention, the invention also provides a cover for a head part of a hand instrument for medical, particularly dental, use.

[0015] This allows the cover to be attached to, in particular, known, older medical hand instruments, and therefore allows the improved mechanism for releasing the retention mechanism to be used with other, especially older, hand instruments, so that the benefits of the improved safety of use and ease of operation provided by the cover of the present invention are also available to users of older hand instruments.

[0016] Therefore, the following aspects and configurations of the cover are equally effective for the cover of the present invention and the hand instrument of the present invention.

[0017] In one preferred configuration, the first lever acts on the free end of the second lever when actuated, so that the cooperation of the first and second levers results in a particularly efficient leverage action, and thus the force required to release the retention by the release element and the retention means is significantly reduced.

[0018] Preferably, the pivot axis of the first lever and the pivot axis of the second lever are arranged parallel to one another and perpendicular to the plane of said rotation axes, which results in a particularly space-saving arrangement and a particularly advantageous transmission of forces from the first lever to the second lever.

[0019] Preferably, the pivot axis of the first lever and the pivot axis of the second lever are arranged opposite each other with respect to said axis of rotation, which results in a particularly advantageous arrangement of the two levers. Even more preferably, the two pivot axes are offset from each other in the direction of said axis of rotation. This additional offset arrangement results in an advantageously improved leverage, since the two pivot axes are arranged advantageously far from each other and the potential length of the levers is increased.

[0020] Preferably, the second lever has a bent portion which presses the release element so as to interact with the release element. The bent portion limits the force acting on the release element. In particular, the second lever is elastic due to the bent portion, and above a certain force, the force acting on the release element is limited, preventing the application of excessive force. This prevents damage to parts of the hand instrument and improves safety in using the hand instrument.

[0021] Preferably, the second lever is provided with a return spring, in particular an arm spring, in the region of its pivot axis. The return spring is configured to move the first and second levers to a standby position in the absence of actuation of the first lever. In the standby position, the second lever is separated from the release element. Thus, after operating the lever mechanism (first and second levers), both levers automatically return to their standby positions, preventing the second lever from coming into contact with the release element. Thus, safety during use is further improved.

[0022] Preferably, the first lever is provided with a side projection in its end region on the pivot axis side. The side projection serves to hold the first lever in the cover and laterally covers the end region of the second lever. This structure of the first lever ensures that the second lever is held safely when the lever mechanism is not in use (standby position) and also fixes the position of the second lever relative to the first lever. The side projection of the first lever also improves the stability of the first lever.

[0023] Preferably, the first lever is provided with a gripping element in its end region remote from the pivot axis, which simplifies the operation of the lever mechanism for releasing the holding mechanism and also improves the transferability of forces to the first lever. The gripping element also further increases the stability of the first lever.

[0024] Preferably, the first lever has a recess on its underside facing the second lever, which receives at least a portion of the second lever when the two levers are in the standby position, thereby preventing the second lever from shifting. In addition, the two levers are arranged in a space-saving manner, which allows the height of the cover to be reduced.

[0025] Preferably, the cover can be attached to and detached from the head of the hand instrument. Preferably, for this purpose, the cover has a thread and the head part has a corresponding reverse thread. This makes it possible to carry out maintenance, cleaning and repair work on the inside of the head part and on the cover very simple and advantageous. Furthermore, the individual parts of the cover and the head part are also particularly easily accessible.

[0026] Preferably, the cover is provided with a locking device by which the lever mechanism can be selectively locked in any orientation about said axis of rotation, thereby allowing the user to adjust the operating direction of the lever mechanism to his or her preference, making the lever mechanism particularly simple and easy to handle personally.

[0027] In one particular preferred embodiment, the lever mechanism is held movable along said axis of rotation. The lever mechanism is preloaded by a spring force away from the release element. The lever mechanism can be depressed against the spring force and, in the depressed state, comes into contact with the release element when the two levers are in the waiting position. With this particular configuration, in addition to the lever mechanism with the first and second levers, an additional pushing mechanism is implemented for releasing the holding mechanism. By pushing down the cover with the levers in the waiting position, the second lever comes into contact with the release element, thereby releasing the holding in the holding means. In this sense, this embodiment comprises two mechanisms for releasing the holding mechanism.

[0028] Preferably, the holding means is a collet and / or the release element comprises a wedge element having a wedge-shaped head and a flat bottom, in which way a particularly simple and yet stable holding mechanism can be realized with the release element and the holding means.

[0029] More preferably, the first lever is configured as a two-arm lever and the second lever is configured as a single-arm lever, which enhances the leverage of the lever mechanism and at the same time allows the two levers to be arranged in the cover in a space-saving manner.

[0030] The invention will now be explained in more detail using exemplary embodiments and with reference to the following drawings, in which: [Brief description of the drawings]

[0031] [Figure 1] 1 is a schematic side view showing a medical hand instrument according to an embodiment of the present invention, in which a treatment tool is attached to a head part of the hand instrument. FIG. [Diagram 2] 1 is a schematic cross-sectional view showing a first exemplary embodiment of a cover and a medical hand instrument according to the present invention; [Figure 3A] FIG. 11 is a schematic cross-sectional view of a second exemplary embodiment of a cover for a medical hand instrument according to the present invention, with the lever mechanism in an activated position. [Figure 3B] 3B is a perspective view of the embodiment of the cover for medical hand instruments according to the present invention shown in FIG. 3A with the lever mechanism in an actuated position; FIG. [Figure 4A] 3B is a schematic cross-sectional view of the embodiment of the cover for a medical hand instrument according to the present invention shown in FIG. 3A, with the lever mechanism in a standby position; [Figure 4B] 3B is a perspective view of the embodiment of the cover for medical hand instruments according to the present invention shown in FIG. 3A, with the lever mechanism in a standby position; FIG. [Diagram 5] 13 is a schematic cross-sectional view showing a third exemplary embodiment of a cover and a medical hand instrument according to the present invention. FIG. [Figure 6]FIG. 1 is a schematic cross-sectional view of a head region of a medical hand instrument according to the prior art. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] 1 shows the basic structure of a medical, in particular dental, hand instrument 1 according to the invention. At its front end 101, the hand instrument 1 has a head part 20. The head part 20 is connected to a grip sleeve 10 of the hand instrument 1. At the rear end 102 of the hand instrument 1, there is usually provided a connection for a supply line 6, via which the hand instrument 1 can be connected to an energy supply source. In particular, the hand instrument 1 can be supplied with electrical or mechanical energy (e.g. rotational energy) via the supply line 6.

[0033] The parts of the hand instrument that are important for the present invention are shown in detail in Figures 2 to 5. In these figures, the area of ​​the head part 20 is depicted in detail. The present invention aims to improve the mechanism for releasing the holding mechanism of the treatment tool 7 in the head part 20 of the hand instrument 1. This mechanism is implemented in the cover 30 of the hand instrument 1 and is realized as a lever mechanism 304. The cover 30 can be attached to and detached from any of the head parts 20 of the various embodiments disclosed herein.

[0034] The lever mechanism 304 comprises a first lever 320 and a second lever 330 which cooperate to release the holding of the treatment tool 7. For this purpose, the lever mechanism 304 interacts with the release element 210, which activates (or opens) the holding means 230. This allows the treatment tool 7 to be inserted or removed from the head part 20 of the hand instrument 1. The lever mechanism 304 ensures that the force applied by the user is minimized. Moreover, as shown in FIG. 3A, the actuation B of the first lever 320 is made in the opposite direction to the action of the second lever 330 on the release element 210. This required actuation movement B causes the first lever 320 to spread away from the cover 30. Thus, in the lever mechanism 304, an unintended triggering of the release of the holding mechanism is prevented. As a result, there is no risk of burns to the user or the patient due to unintended actuation. This is because any force acting on the cover 30, and in particular on the lever 320 (e.g., due to contact with the patient's cheek or teeth or the fingers of the treating physician) does not trigger the lever mechanism 304, thus preventing the lever mechanism 304 from coming into contact with rapidly rotating parts during operation of the hand instrument 1.

[0035] Regardless of the specific embodiment of the cover 30, the lever mechanism 304 mounted on the cover 30 is always configured to interact with the release element 210 by an actuation B, so that the release element 210 releases the holding means 230. The holding means 230 and the release element 210 constitute a so-called holding mechanism. As shown in FIG. 2, the holding means 230 is preferably a collet. That is, the holding means 230 is a cylindrical sleeve having a stepped hole and at least one slot. The holding means 230 is opened by the release element 210 when actuated. The release element 210 preferably has a wedge-shaped head 211 and a flat bottom 212. For example, the wedge-shaped head 211 of the release element 210 interacts with the slot of the collet and spreads the sleeve of the collet. This allows the treatment tool 7 to be inserted into and removed from the holding means 230 through the tool receptacle 240 and the tool channel 250 of the head part 20. For this purpose, the release element 210 must be actively pushed in the direction of the retaining means 230 (this is achieved in particular by actuation B of the lever mechanism 304), since the interaction of the two parts of the retaining mechanism is automatic, i.e. the retaining means 230 itself pushes out the release element 210.

[0036] For this purpose, in the head part 20, the release element 210 and the holding means 230 are arranged in a given recess 260, the diameter of which is larger than the diameter of the tool receptacle 240 and the tool channel 250, so that the parts of the holding mechanism are safely accommodated in the head part 20. In particular, the holding means 230 and the release element 210 are supported rotatably together with the treatment tool 7 and, in use, rotate at the same speed as the treatment tool 7. In this case, the parts of the holding mechanism also serve to center the tool.

[0037] 2 shows a first exemplary embodiment of the cover 30. This cover 30 is fastened via a screw 302 to a head part 20 having a corresponding reverse thread 220. A lever mechanism 304 is arranged in a central part 301 of the cover 30. In this first exemplary embodiment, the central part 301 is arranged in a freely rotatable manner with respect to an outer part 305 that annularly surrounds the central part 301. This allows the orientation of the lever mechanism 304 (in particular the orientation of the first lever 320 operated by the user) to be changed depending on the situation. The screw 302 is arranged in the outer part 305.

[0038] The first lever 320 (sometimes referred to as the upper lever 320) is provided with a grip element 322 for greatly facilitating the operation of the lever mechanism 304. Opposite to the grip element 322, the first lever 320 is provided with a number of side projections 323. Each side projection 323 has an attachment portion 326 for attaching the lever 320 to the cover 30 and laterally overlaps an end of the second lever 330. With this structure, the two levers 320, 330 are arranged on the cover 30 in a space-saving manner in the standby position P, as shown in FIG. 4A. The side projections 323, together with the respective attachment portions 326, form a pivot axis X of the first lever 320. The pivot axis X is arranged so that the first lever 320 is a two-arm lever. The pivot axis X of the first lever 320 is distant from both the grip element 322 and the end of the first lever 320 opposite the grip element 322.

[0039] The end of the first lever 320 facing away from the gripping element 322 forms a contact surface 329 of the first lever 320, which acts on the free end of the second lever 330 during an actuation B of the lever mechanism 304. This free end has a contact surface 339, which interacts with the contact surface 329 of the first lever 320. The gripping element 322 and the contact surface 329 of the first lever 320 are connected by a long bar 321. The contact 340 between the first lever 320 and the second lever 330 is always present via the contact surfaces 329, 339 and is not interrupted even in the waiting position P. Thus, even a slight actuation B of the first lever 320 causes a movement of the second lever 330.

[0040] Furthermore, the first lever 320 has a recess 324 on its lower surface facing the second lever 330. The recess 324 accommodates at least a portion of the second lever 330 in the standby position P. This allows the second lever 330 to be stored in a space-saving manner.

[0041] The second lever 330 (sometimes referred to as the lower lever 330) is configured as a single-arm lever. The attachment portion 334 is disposed on the opposite side of the contact surface 339. The attachment portion 334 configures the pivot axis Y of the second lever 330.

[0042] Between the contact surface 339 and the mounting portion 334, the second lever has a bent portion 331. The bent portion 331 presses the release element 210 so as to interact with it. The bent portion 331 limits the force applied to the release element 210. The bent portion 331 makes the second lever 330 elastic. This ensures that above a certain lever force, the lower lever 330 does not bend any further, preventing excessive force from acting on the release element 210. The bent portion 331 is arranged in the center of the cover 30. This ensures that the bent portion 331 is always located on the axis of rotation M, regardless of the orientation of the central part 301, and thus ensures an optimal force transmission in interaction with the release element 210 by the actuation B.

[0043] The second lever 330 is provided with a return spring 332 (in particular an arm spring) in the region of the pivot axis Y. The return spring 332 is configured to return the first lever 320 and the second lever 330 to the waiting position P when no actuation B of the first lever 320 takes place. The return spring 332 in this case has a flat support 333 on which the return spring 332 acts and the restoring force pushes the second lever upwards (i.e. towards the first lever 320). As a result, the upper lever 320 returns and is pushed towards the waiting position P, unless the first lever 320 is actuated.

[0044] The mounting part 326 of the first lever 320 and the mounting part 336 of the second lever 330, or their pivot axes X and Y, are arranged parallel to each other and perpendicular to a plane along the axis of rotation M. This allows for particularly good force transmission from the lever mechanism 304 to the release element 210 located on the axis of rotation M.

[0045] Furthermore, the mounting portion 326 of the first lever 320 and the mounting portion 336 of the second lever 330, or their pivot axes X and Y, are arranged on opposite sides of the cover with respect to the rotation axis M. The two-arm structure of the first lever 320 and the single-arm structure of the second lever 330 allow for a particularly efficient transmission of force. Due to the overlapping arrangement of the first lever 320 and the second lever 330, the two pivot axes X and Y are slightly offset from each other even in the direction of the rotation axis M.

[0046] In the standby position P, the second lever 330 is spaced apart from the release element 210, so that unintentional contact between these two elements is prevented.

[0047] Furthermore, the first lever 320 preferably comprises a latch element 325 below the grip element 322, which interacts with the second lever 330 in the waiting position P to latch them together, thereby providing the user with tactile and acoustic feedback when both levers 320 and 330 are correctly positioned in the waiting position P. The safety of the operation of the hand instrument 1 is also increased, since the latch provides an additional mechanical fixation in the lever mechanism 304, preventing an accidental lifting of the first lever 320 (and thus an actuation B of the lever mechanism 304).

[0048] The two-part lever mechanism 304 significantly reduces the force applied by the user, which would be felt even with a single lever mechanism. However, the lever will inevitably rub against the release element 210, since the contact surface of the lever will move laterally relative to the release element 210. This will have the disadvantage of material wear on both elements, which would significantly reduce the safety of operating the hand instrument 1. In this respect, the two-part lever mechanism 304 is advantageous in this application.

[0049] 3A, 3B, 4A and 4B show a second exemplary embodiment of the cover 30 according to the present invention. The cover 30 is detachable from the hand instrument 1. The structure of this second embodiment is substantially the same as the first exemplary embodiment shown in FIG. 2. The three-dimensional structure of the cover 30 is made clearer by the illustration excluding other components of the hand instrument 1 (particularly the components of the holding mechanism are not shown). FIGS. 3B and 4B show perspective views of the cover 30 and its lever mechanism 304. This perspective view is the same as that of the first embodiment.

[0050] The second embodiment has further additional features that further improve the ease of handling and the safety of operation. In this case, an additional locking device 310 is provided. The locking device 310 can lock a set orientation of the lever mechanism 304 about the rotation axis M. After locking, unintended rotation of the central part 301 is prevented. Of course, the locking of the locking device 310 can be released again. This allows the lever mechanism 304 and the associated central part 301 to be reoriented and locked again. As is clear from FIGS. 3A-4B, in the variant shown here, the locking device 310 is an overnut device and consists of a ring element 311. The ring element 311 has a thread and is arranged to interact with an inner thread 303 arranged on the inside of the threaded part. The ring element 311 in this case is arranged between the central part 301 and the outer part 305. The ring element 311, when screwed in appropriately, fixes the central part 301 by a force fit (Kraftschluss). For this purpose, the ring element 311 has recesses 319 for suitable tools for screwing in. This allows a secure locking. This embodiment with the fixing device 310 allows the hand instrument 1 or the cover 30 to be adapted to the individual requirements and preferences of the user. For example, a left-handed user can set the lever mechanism 304 in a different orientation. This significantly increases the comfort of use of the hand instrument 1.

[0051] Furthermore, the outer part 305 can also have a recess 309 for a suitable tool, which allows a secure screw connection of the cover 30 with the head part 20 of the hand instrument 1. In particular, such an embodiment makes it impossible to separate these parts without a tool, which further increases the safety of operating the hand instrument 1.

[0052] As is also evident from Figures 3A and 4B, the outer part 305 can be extended below the central part 301. This improves the stability of the cover. In this case, the central part 301 is further supported rotatably in the outer part 305 via a ball bearing 312. This makes it easy to change the orientation of the central part 301 and the lever mechanism 304 along the rotation axis M. The locking device 310 likewise locks the ball bearing 312, preventing further rotation of the central part 301. These configurations can also be applied to the first embodiment shown in Figure 2, either in whole or individually.

[0053] The cover 30 has a receiving space 350. The receiving space 350 receives the components of the head part 20 when the cover 30 is connected to the hand instrument 1. What is important here is that the movement of the second lever 330 is not restricted, so that the bent portion 331 can interact with the release element 210 of the head part 20 upon actuation B of the lever mechanism 304. This structure is also applicable to the embodiment shown in FIG. 2.

[0054] Figures 3A and 3B show the operating position B of the lever mechanism 304. When viewed in conjunction with Figures 4A and 4B, which show the standby position P of the lever mechanism 304, the possible lever positions are made clear. This representation of the operating B and standby positions is applicable to all exemplary embodiments. Of course, other configurations of the two-part lever mechanism are also contemplated.

[0055] As can be seen especially from Figures 4A and 4B, the lever mechanism 304 is configured in such a way that the first lever 320 is integrated planarly into the surface of the central part 301. Only the grip element 322 protrudes a little from the central part 301, which allows for particularly easy manipulation by the user.

[0056] 5 further shows a third exemplary embodiment of the cover 30 and the hand instrument 1. This embodiment has, in addition to the two-part lever mechanism 304 known from the first and second embodiments, an additional mechanism for releasing the retention mechanism.

[0057] In this case, a spring element 40 is disposed between the cover 30 and the head piece 20. In this embodiment, the cover 30 (and thus the lever mechanism 304) is held for movement along a rotational axis M. The spring element 40 urges the cover 30 away from the head piece 20. Thus, the lever mechanism 304 is preloaded by the force of the spring element 40 to a position away from the release element 210.

[0058] The cover 30 and the head part 20 in this embodiment are connected via the screw 302 and the counterscrew 220 as before. However, this connection is configured so that the cover 30 can reciprocate along a smooth surface after being fastened via the screws 302 and 220. The screws 302 and 220 prevent the cover 30 from being unintentionally separated from the head part 20. In this embodiment, the lever mechanism 304 can be depressed against the spring force. The lever mechanism 304 contacts the release element 210 in the depressed state when the two levers 320 and 330 are in the standby position.

[0059] In this connection, in the third exemplary embodiment, both the lever mechanism 304 and the push button mechanism for releasing the holding mechanism are integrated in the cover 30. This allows the user to choose which mechanism to use. In this embodiment, for example, a particularly strong spring element 40 can be used, which is not compressed by light contact or by the action of force on the cover 30. This prevents unintended contact with the lever mechanism 304 during operation of the hand instrument 1. However, in this case, the user of the hand instrument 1 needs a large force to couple (i.e. clamp) or separate (i.e. release) the treatment tool 7 to the hand instrument 1. A user who is unable to exert the necessary force can simply release the holding mechanism of the hand instrument 1 using the lever mechanism 304.

[0060] All the above-mentioned exemplary embodiments of the hand instrument 1 and the cover 30 make the release of the treatment tool 7 much easier. In the present case, the cover 30 is advantageously configured so that it can also be fixed by means of a screw to older hand instruments 1 known from the past. This allows the two-part lever mechanism 304 according to the invention to be applied to older hand instruments 1 as well. The removable configuration of the cover 30 allows particularly simple and advantageous maintenance, cleaning and repair operations to be carried out on the inside of the head part 20 and on the cover 30 itself. This allows the service life of the hand instrument 1 and the cover 30 to be extended.

[0061] The hand instrument 1 configured in this way, and the cover 30 configured for the hand instrument 1 in this way, make the operation of releasing the holding mechanism of the treatment tool 7 on the hand instrument 1 particularly simple and safe, thereby avoiding unintended activation of the mechanism and in particular preventing the lever mechanism 304 from coming into contact with the release element 210 during operation, so that there is no risk of burns for the patient or the treating physician.

Claims

1. A grip sleeve (10); a head piece (20) disposed at a front end (101) of the grip sleeve (10) and having a tool receiving opening (240); A hand instrument (1) for medical, in particular dental, use, comprising: a holding means (230) for rotatably holding a treatment tool (7), e.g. a dental drill, is arranged inside said head part (20); said holding means (230) being arranged along the axis of rotation (M) of said treatment tool (7); a release element (210) arranged inside said head part (20) along said axis of rotation (M) and adapted to interact with said retaining means (230); said release element (210) interacting with said holding means (230) to release the holding of said treatment tool (7); The head component (20) further includes a cover (30), The cover (30) has a lever mechanism (304) having a first lever (320) and a second lever (330) that cooperate to release the retention of the treatment tool (7). A hand instrument for medical, particularly dental, use, characterized in that

2. said first lever (320) acts on the free end of said second lever (330) when actuated; 2. The medical hand instrument according to claim 1 .

3. The pivot axis (X) of the first lever (320) and the pivot axis (Y) of the second lever (330) are arranged parallel to each other and perpendicular to a plane along the rotation axis (M).

3. The medical hand instrument according to claim 1 or 2.

4. The pivot axis (X) of the first lever (320) and the pivot axis (Y) of the second lever (330) are disposed on opposite sides of the cover with respect to the rotation axis (M); Preferably, the two pivot axes (X, Y) are offset from one another in the direction of the rotation axis (M), 4. The medical hand instrument according to claim 3.

5. the second lever (330) has a bent portion (331) which presses the release element (210) to interact with the release element (210), the bent portion (331) limiting the force applied to the release element (210); 4. A medical hand instrument according to any one of the preceding claims.

6. said second lever (330) is provided with a return spring (332), in particular an arm spring, in the region of its pivot axis (Y); the return spring is configured to move the first and second levers (320, 330) to a standby position (P) when there is no actuation (B) of the first lever (320); In the standby position (P), the second lever (330) is separated from the release element (210).

4. A medical hand instrument according to any one of the preceding claims.

7. the first lever (320) is provided at its end region on the side of the pivot axis (X) with a lateral projection (323) which serves to hold the lever (320) in the head part (30) and which laterally covers the end region of the second lever (330); 4. A medical hand instrument according to any one of the preceding claims.

8. said first lever (320) is provided in its end region remote from said pivot axis (X) with a grip element (322); 4. A medical hand instrument according to any one of the preceding claims.

9. The first lever (320) has a recess (324) on a lower surface facing the second lever (330) for receiving at least a portion of the second lever (330) when the two levers (320, 330) are in the standby position (P).

4. A medical hand instrument according to any one of the preceding claims.

10. The cover (30) is detachable from the head part (20) of the hand instrument (1); Preferably, for this purpose, the cover (30) has a thread (302) and the head part (20) has a corresponding reverse thread (220).

4. A medical hand instrument according to any one of the preceding claims.

11. The cover (30) is provided with a fixing device (310), the lever mechanism (304) can be selectively locked in any orientation about the axis of rotation (M) by the locking device (310); 4. A medical hand instrument according to any one of the preceding claims.

12. The lever mechanism (304) is held movably along the rotation axis (M), the lever mechanism (304) is preloaded by a spring force away from the release element (210); The lever mechanism (304) can be depressed against the spring force, and when the two levers (320, 330) are in the standby position (P), the lever mechanism (304) comes into contact with the release element (210) in the depressed state.

11. A medical hand instrument according to any one of claims 1 to 10.

13. the retaining means (230) is a collet and / or the release element (210) is a wedge element having a wedge-shaped head (211) and a flat bottom (212); 13. A medical hand instrument according to any one of claims 1 to 12.

14. A grip sleeve (10); a head piece (20) disposed at a front end (101) of the grip sleeve (10) and having a tool receiving opening (240); A cover (30) for a head part (20) of a medical, in particular dental, hand instrument (1), comprising: a holding means (230) for rotatably holding a treatment tool (7), e.g. a dental drill, is arranged inside said head part (20); said holding means (230) being arranged along the axis of rotation (M) of said treatment tool (7); a release element (210) arranged inside said head part (20) along said axis of rotation (M) and adapted to interact with said retaining means (230); said release element (210) interacting with said holding means (230) to release the holding of said treatment tool (7); The cover (30) has a lever mechanism (304) having a first lever (320) and a second lever (330) that cooperate to release the retention of the treatment tool (7). A cover for a head part of a hand instrument for medical use, particularly for dentistry, characterized in that:

15. The first lever (320) is configured as a two-arm lever, and the second lever (330) is configured as a single-arm lever. The head component cover according to claim 14 .

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